JP7103832B2 - Light receiving element and manufacturing method of light receiving element - Google Patents

Light receiving element and manufacturing method of light receiving element Download PDF

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JP7103832B2
JP7103832B2 JP2018080000A JP2018080000A JP7103832B2 JP 7103832 B2 JP7103832 B2 JP 7103832B2 JP 2018080000 A JP2018080000 A JP 2018080000A JP 2018080000 A JP2018080000 A JP 2018080000A JP 7103832 B2 JP7103832 B2 JP 7103832B2
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light receiving
metal film
receiving element
light
recess
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JP2019192675A (en
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領 杉森
祐馬 田中
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Hamamatsu Photonics KK
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Priority to US17/042,509 priority patent/US11380724B2/en
Priority to CN201980026029.8A priority patent/CN111989784A/en
Priority to PCT/JP2019/015499 priority patent/WO2019203070A1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
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    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
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    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/18—Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
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    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14683—Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof
    • H01L27/14685—Process for coatings or optical elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0232—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/02—Details
    • H01L31/0236—Special surface textures
    • H01L31/02366—Special surface textures of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
    • H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
    • H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
    • H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
    • H01L31/103—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PN homojunction type
    • H01L31/1037—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PN homojunction type the devices comprising active layers formed only by AIVBVI compounds

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  • Light Receiving Elements (AREA)
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Description

本発明は、受光素子、及び、受光素子の製造方法に関する。 The present invention relates to a light receiving element and a method for manufacturing the light receiving element.

特許文献１には、光伝導型赤外線検出器が記載されている。この検出器は、赤外線を吸収する結晶に対して遮光マスクを設けている。遮光マスクには、受光部を提供する開口が設けられている。また、遮光マスクには、周期的な凹凸が形成されている。そして、当該凹凸の間隔及び段差に係るパラメータが、遮光マスクから撮像装置の光学系に直接戻る赤外線に対して弱め合う干渉条件を満たすように設定されている。 Patent Document 1 describes a photoconducting infrared detector. This detector is provided with a light-shielding mask for crystals that absorb infrared rays. The light-shielding mask is provided with an opening that provides a light-receiving portion. Further, the light-shielding mask is formed with periodic irregularities. Then, the parameters related to the interval and the step of the unevenness are set so as to satisfy the interference condition that weakens against the infrared rays directly returning from the light-shielding mask to the optical system of the image pickup apparatus.

特許文献２には、半導体受光装置が記載されている。この受光装置は、ｎ型ＩｎＰ基板と、ｎ型ＩｎＰ基板上に形成されたｎ型ＩｎＰ層と、ｎ型ＩｎＰ層上に形成されたｐ型ＩｎＰ層と、ｐ型ＩｎＰ層の一部に開口するようにｐ型ＩｎＰ層上に形成された誘電体膜と、誘電体膜上に形成され、受光部以外へ入射する光を遮光する遮光マスク用の金属層と、を備えている。金属層の表面には凹凸が形成されている。 Patent Document 2 describes a semiconductor light receiving device. This light receiving device has an opening in a part of the n-type InP substrate, the n-type InP layer formed on the n-type InP substrate, the p-type InP layer formed on the n-type InP layer, and the p-type InP layer. A dielectric film formed on the p-type InP layer and a metal layer for a light-shielding mask formed on the dielectric film to block light incident on a light-receiving portion other than the light-receiving portion are provided. Unevenness is formed on the surface of the metal layer.

特開平４－８４４６２号公報Japanese Unexamined Patent Publication No. 4-84462 特許第２７７４００６号公報Japanese Patent No. 2774006

特許文献１に記載された検出器にあっては、遮光マスクの周期的な凹凸のパラメータを、戻り光に対して弱め合う干渉条件を満たすように設定することにより、赤外画像の乱れをなくすことを図っている。また、特許文献２に記載された受光装置にあっては、遮光マスク用の金属層の表面に凹凸を形成して入射光を乱反射させることにより、戻り光によるノイズの防止を図っている。このように、上記技術分野にあっては、遮光部における反射率を低減することが望まれている。 In the detector described in Patent Document 1, the disturbance of the infrared image is eliminated by setting the parameter of the periodic unevenness of the light-shielding mask so as to satisfy the interference condition that weakens against the return light. I'm trying to do that. Further, in the light receiving device described in Patent Document 2, noise due to the return light is prevented by forming irregularities on the surface of the metal layer for the light shielding mask to diffusely reflect the incident light. As described above, in the above technical field, it is desired to reduce the reflectance in the light-shielding portion.

本発明は、遮光部における反射率を低減可能な受光素子、及び、受光素子の製造方法を提供することを目的とする。 An object of the present invention is to provide a light receiving element capable of reducing the reflectance in a light shielding portion and a method for manufacturing the light receiving element.

本発明に係る受光素子は、受光部と遮光部とを含む第１面を有する半導体部と、遮光部上に設けられた遮光のための金属膜と、を備え、金属膜は、第１面と反対側に臨み光の入射を受ける第２面を有し、第２面には、複数の凹部が形成されており、凹部の内面は、第２面から凹部の底部に向かうにつれて第２面に沿った方向における凹部のサイズが縮小するように曲がる曲面部を含む。 The light-receiving element according to the present invention includes a semiconductor portion having a first surface including a light-receiving portion and a light-shielding portion, and a metal film for light-shielding provided on the light-shielding portion, and the metal film is the first surface. It has a second surface that faces the opposite side and receives light incident on it, and a plurality of recesses are formed on the second surface, and the inner surface of the recess is the second surface as it goes from the second surface to the bottom of the recess. Includes a curved surface that bends to reduce the size of the recess in the direction along.

この受光素子においては、半導体部の第１面の遮光部上に、遮光のための金属膜が形成されている。金属膜は、第１面と反対側に臨む第２面を有する。第２面には、複数の凹部が形成されている。そして、凹部の内面は、金属膜の第２面から凹部の底部に向かうにつれて凹部が縮小するように曲がる曲面部を含む。このため、金属膜の第２面に入射した光の一部が、凹部の内面の曲面部によって種々の方向に反射されて拡散される。この結果、遮光部における反射率が低減される。 In this light receiving element, a metal film for light shielding is formed on the light shielding portion on the first surface of the semiconductor portion. The metal film has a second surface facing the opposite side of the first surface. A plurality of recesses are formed on the second surface. The inner surface of the recess includes a curved surface that bends so that the recess shrinks from the second surface of the metal film toward the bottom of the recess. Therefore, a part of the light incident on the second surface of the metal film is reflected and diffused in various directions by the curved surface portion of the inner surface of the recess. As a result, the reflectance in the light-shielding portion is reduced.

本発明に係る受光素子においては、曲面部は、底部を構成するように延在していてもよい。この場合、凹部の内面の全体が曲面部となるため、入射光を確実に拡散させることができる。 In the light receiving element according to the present invention, the curved surface portion may extend so as to form a bottom portion. In this case, since the entire inner surface of the recess is a curved surface, the incident light can be reliably diffused.

本発明に係る受光素子においては、第２面における凹部のサイズは、第２面に交差する方向における金属膜のサイズ以下であってもよい。この場合、第２面における凹部のサイズを直径とする半球面状に曲面部を形成しても、凹部の底部の直下に金属膜を残存させて遮光性を十分に維持できる。 In the light receiving element according to the present invention, the size of the recess on the second surface may be smaller than or equal to the size of the metal film in the direction intersecting the second surface. In this case, even if the curved surface portion is formed in a hemispherical shape having the diameter of the recessed portion on the second surface, the metal film can be left directly under the bottom portion of the recessed portion to sufficiently maintain the light-shielding property.

本発明に係る受光素子においては、第２面は、凹部の周囲に設けられた平坦な領域を含んでもよい。この場合、第２面における平坦な領域で反射した光と、凹部の内面で反射した光との干渉によって、反射率を確実に低減可能である。 In the light receiving element according to the present invention, the second surface may include a flat region provided around the recess. In this case, the reflectance can be reliably reduced by the interference between the light reflected in the flat region on the second surface and the light reflected on the inner surface of the recess.

本発明に係る受光素子においては、凹部は、第２面に沿って一定のピッチで配列されていてもよい。この場合、凹部の形成を容易化できる。 In the light receiving element according to the present invention, the recesses may be arranged at a constant pitch along the second surface. In this case, the formation of the recess can be facilitated.

ここで、本発明に係る受光素子の製造方法は、半導体部の第１面の一部上に遮光のための金属膜を形成することにより、金属膜から露出した受光部と金属膜に覆われた遮光部とを第１面に形成する第１工程と、金属膜における第１面と反対側に臨む第２面の等方性のエッチングにより、第２面に複数の凹部を形成する第２工程と、を備える。 Here, in the method for manufacturing a light receiving element according to the present invention, a metal film for shading is formed on a part of the first surface of the semiconductor part, so that the light receiving part exposed from the metal film and the metal film are covered with the metal film. A second step of forming a plurality of recesses on the second surface by isotropic etching of the first step of forming the light-shielding portion on the first surface and the second surface of the metal film facing the opposite side of the first surface. It is equipped with a process.

この製造方法によれば、受光部と遮光部とを含む第１面を有する半導体部と、遮光部上に設けられ、複数の凹部が形成された金属膜と、を備える受光素子が製造される。特に、金属膜の第２面の等方性エッチングによって、凹部の内面を、金属膜の第２面から凹部の底部に向かうにつれて凹部が縮小するように曲がる曲面部を含むように形成できる。したがって、この製造方法によれば、遮光部における反射率が低減された受光素子を製造できる。 According to this manufacturing method, a light-receiving element including a semiconductor portion having a first surface including a light-receiving portion and a light-shielding portion, and a metal film provided on the light-shielding portion and having a plurality of recesses formed therein is manufactured. .. In particular, by isotropic etching of the second surface of the metal film, the inner surface of the recess can be formed to include a curved surface portion that bends so that the recess shrinks from the second surface of the metal film toward the bottom of the recess. Therefore, according to this manufacturing method, it is possible to manufacture a light receiving element having a reduced reflectance in the light-shielding portion.

本発明に係る受光素子の製造方法においては、等方性のエッチングは、ウェットエッチングであってもよい。この場合、ドライエッチングと比較して、エッチングにより形成される凹部の内面が粗面化される。このため、遮光部における反射率がより低減された受光素子を製造できる。 In the method for manufacturing a light receiving element according to the present invention, the isotropic etching may be wet etching. In this case, the inner surface of the recess formed by etching is roughened as compared with dry etching. Therefore, it is possible to manufacture a light receiving element having a reduced reflectance in the light shielding portion.

本発明によれば、遮光部における反射率を低減可能な受光素子、及び、受光素子の製造方法を提供できる。 According to the present invention, it is possible to provide a light receiving element capable of reducing the reflectance in the light shielding portion and a method for manufacturing the light receiving element.

実施形態に係るロータリーエンコーダを示す模式的な斜視図である。It is a schematic perspective view which shows the rotary encoder which concerns on embodiment. 図１に示された受光素子の平面図である。It is a top view of the light receiving element shown in FIG. 図２のIII－III線に沿っての部分断面図である。It is a partial cross-sectional view along the line III-III of FIG. 図３に示された凹部を示す図である。It is a figure which shows the concave part shown in FIG. 図３に示された受光素子を簡素化した受光素子を示す部分断面図である。It is a partial cross-sectional view which shows the light receiving element which simplified the light receiving element shown in FIG. 図５に示された受光素子の製造方法の主な工程を示す部分断面図である。It is a partial cross-sectional view which shows the main process of the manufacturing method of the light receiving element shown in FIG. 図５に示された受光素子の製造方法の主な工程を示す部分断面図である。It is a partial cross-sectional view which shows the main process of the manufacturing method of the light receiving element shown in FIG. 図５に示された受光素子の製造方法の主な工程を示す部分断面図である。It is a partial cross-sectional view which shows the main process of the manufacturing method of the light receiving element shown in FIG. 図５に示された受光素子の製造方法の主な工程を示す部分断面図である。It is a partial cross-sectional view which shows the main process of the manufacturing method of the light receiving element shown in FIG. 図５に示された受光素子の製造方法の主な工程を示す部分断面図である。It is a partial cross-sectional view which shows the main process of the manufacturing method of the light receiving element shown in FIG. 実施例及び変形例に係る受光素子の金属膜の一部を示す写真である。It is a photograph which shows a part of the metal film of the light receiving element which concerns on Example and the modification. 実施例及び比較例に係る受光素子の反射率を示すグラフである。It is a graph which shows the reflectance of the light receiving element which concerns on Example and the comparative example. 変形例に係る受光素子の部分断面図である。It is a partial cross-sectional view of the light receiving element which concerns on the modification. 変形例に係る金属膜を示す図である。It is a figure which shows the metal film which concerns on the modification. 変形例に係る金属膜を示す平面図である。It is a top view which shows the metal film which concerns on the modification. 変形例に係る金属膜を示す平面図である。It is a top view which shows the metal film which concerns on the modification.

以下、本発明の一実施形態について、図面を参照して詳細に説明する。なお、各図において、同一の要素同士、或いは、相当する要素同士には、互いに同一の符号を付し、重複する説明を省略する場合がある。 Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each figure, the same elements or the corresponding elements may be designated by the same reference numerals, and duplicate description may be omitted.

図１は、実施形態に係るロータリーエンコーダを示す模式的な斜視図である。図１に示されるように、ロータリーエンコーダ１００は、コードホイール１０１、回転軸１０２、発光素子１０３、及び、受光素子１を備えている。コードホイール１０１は、例えばガラスや金属等により円板状に形成されている。コードホイール１０１の外周部には、周方向に沿って複数のスリット１０１ｓが形成されている。回転軸１０２は、コードホイール１０１の中心に設けられており、図示しない駆動部の動作に応じた回転量によりコードホイール１０１を回転させる。 FIG. 1 is a schematic perspective view showing a rotary encoder according to an embodiment. As shown in FIG. 1, the rotary encoder 100 includes a chord wheel 101, a rotating shaft 102, a light emitting element 103, and a light receiving element 1. The chord wheel 101 is formed in a disk shape, for example, from glass, metal, or the like. A plurality of slits 101s are formed on the outer peripheral portion of the chord wheel 101 along the circumferential direction. The rotation shaft 102 is provided at the center of the chord wheel 101, and rotates the chord wheel 101 by a rotation amount corresponding to the operation of a drive unit (not shown).

発光素子１０３及び受光素子１は、コードホイール１０１を挟むように互いに対向して配置されている。発光素子１０３、例えば、半導体発光素子であって、発光ダイオードやレーザダイオード等である。コードホイール１０１と発光素子１０３の間には、図示しない固定スリット板が介在される。受光素子１は、例えば、半導体受光素子であって、フォトダイオード等である。受光素子１の受光面（後述する第１面１ｓ及び第２面５ｓ）は、コードホイール１０１の板面に対向している。受光素子１は、図示しないコンピュータ等に電気的に接続されており、入射光に応じて発生した電気信号を出力する。 The light emitting element 103 and the light receiving element 1 are arranged so as to face each other so as to sandwich the chord wheel 101. The light emitting element 103, for example, a semiconductor light emitting element, such as a light emitting diode or a laser diode. A fixed slit plate (not shown) is interposed between the chord wheel 101 and the light emitting element 103. The light receiving element 1 is, for example, a semiconductor light receiving element, such as a photodiode. The light receiving surfaces of the light receiving element 1 (first surface 1s and second surface 5s, which will be described later) face the plate surface of the chord wheel 101. The light receiving element 1 is electrically connected to a computer or the like (not shown), and outputs an electric signal generated in response to the incident light.

ロータリーエンコーダ１００においては、発光素子１０３から出射された光が、固定スリット板のスリット及びコードホイール１０１のスリット１０１ｓを介して受光素子１に入射される。このとき、コードホイール１０１の回転により入射光の光量が周期的に変化する。受光素子１は、光量の変化に応じた電気信号を出力する。受光素子１から出力された電気信号がコンピュータ等に入力されることにより、コードホイール１０１の回転量が検出される。 In the rotary encoder 100, the light emitted from the light emitting element 103 is incident on the light receiving element 1 through the slit of the fixed slit plate and the slit 101s of the chord wheel 101. At this time, the amount of incident light changes periodically due to the rotation of the chord wheel 101. The light receiving element 1 outputs an electric signal according to a change in the amount of light. The amount of rotation of the chord wheel 101 is detected by inputting an electric signal output from the light receiving element 1 to a computer or the like.

上述したように、受光素子１の受光面とコードホイール１０１の板面とは、互いに近接及び対向して配置される。このため、受光面での反射光が、コードホイール１０１の板面で反射されて再び受光面に入射するおそれがある。これを抑制するためには、コードホイール１０１の板面に反射防止膜を形成することが一案である。しかしながら、この場合には、コードホイール１０１の製造コストが増大する。したがって、この問題を解決するためには、受光素子１の受光面の反射率を低減することが有効と考えられる。また、受光面の反射率を低減する要求は、受光素子１をロータリーエンコーダ１００に用いる場合に限らず、受光面に対向する他の部材が近接して配置される構成や、その他の構成においても同様に存在する。 As described above, the light receiving surface of the light receiving element 1 and the plate surface of the chord wheel 101 are arranged close to each other and facing each other. Therefore, the reflected light on the light receiving surface may be reflected by the plate surface of the chord wheel 101 and re-enter the light receiving surface. In order to suppress this, it is an idea to form an antireflection film on the plate surface of the chord wheel 101. However, in this case, the manufacturing cost of the chord wheel 101 increases. Therefore, in order to solve this problem, it is considered effective to reduce the reflectance of the light receiving surface of the light receiving element 1. Further, the requirement for reducing the reflectance of the light receiving surface is not limited to the case where the light receiving element 1 is used for the rotary encoder 100, but also in a configuration in which other members facing the light receiving surface are arranged close to each other or in other configurations. It exists as well.

引き続いて、受光素子１について説明する。図２は、図１に示された受光素子の平面図である。図３は、図２のIII－III線に沿っての部分断面図である。図２，３に示されるように、受光素子１は、半導体部２と、絶縁膜３Ａ，３Ｂと、配線層４と、金属膜５と、を備えている。半導体部２は、例えば、シリコンを含む（一例としてシリコン基板である）。半導体部２は、受光面である第１面１ｓを含む。半導体部２の第１面１ｓ側の一部の領域には、第１面１ｓに露出するように拡散層２ｍが形成されている。 Subsequently, the light receiving element 1 will be described. FIG. 2 is a plan view of the light receiving element shown in FIG. FIG. 3 is a partial cross-sectional view taken along the line III-III of FIG. As shown in FIGS. 2 and 3, the light receiving element 1 includes a semiconductor portion 2, insulating films 3A and 3B, a wiring layer 4, and a metal film 5. The semiconductor unit 2 contains, for example, silicon (for example, a silicon substrate). The semiconductor unit 2 includes a first surface 1s which is a light receiving surface. A diffusion layer 2m is formed in a part of the region of the semiconductor portion 2 on the first surface 1s side so as to be exposed on the first surface 1s.

第１面１ｓは、複数の受光部１Ａと単一の遮光部１Ｂとを含む。受光部１Ａは、拡散層２ｍに対応して設けられている。すなわち、受光部１Ａは、半導体部２において入射光を電気信号に変換する領域への光入射部となる。遮光部１Ｂは、配線層４及び／又は金属膜５によって遮光されている。換言すれば、第１面１ｓのうち、第１面１ｓに交差（直交）する方向からみて、配線層４及び／又は金属膜５に覆われているエリアが遮光部１Ｂであり、配線層４及び／又は金属膜５から露出しているエリアが受光部１Ａである。ここでは、金属膜５に設けられた開口５ｈによって受光部１Ａが提供される。 The first surface 1s includes a plurality of light receiving portions 1A and a single light shielding portion 1B. The light receiving portion 1A is provided corresponding to the diffusion layer 2m. That is, the light receiving unit 1A is a light incident unit in the semiconductor unit 2 that converts the incident light into an electric signal. The light-shielding portion 1B is shielded by the wiring layer 4 and / or the metal film 5. In other words, of the first surface 1s, the area covered by the wiring layer 4 and / or the metal film 5 when viewed from the direction intersecting (orthogonal) with the first surface 1s is the light-shielding portion 1B, and the wiring layer 4 And / or the area exposed from the metal film 5 is the light receiving portion 1A. Here, the light receiving portion 1A is provided by the opening 5h provided in the metal film 5.

絶縁膜３Ａは、第１面１ｓ上に設けられている。絶縁膜３Ａは、例えばシリコン酸化物（例えばＳｉＯ２）からなる。配線層４は、絶縁膜３Ａ上に設けられている。配線層４は、例えば、アルミニウム、アルミニウム合金（例えば、アルミニウムと銅やシリコンとの合金）、タングステン、チタン、又は、窒化チタン等からなる。絶縁膜３Ａには、開口３Ａｈ（コンタクトホール）が形成されており、配線層４は、この開口３Ａｈを介して半導体部２（拡散層２ｍ）に接触して電気的に接続されている。 The insulating film 3A is provided on the first surface 1s. The insulating film 3A is made of, for example, a silicon oxide (for example, SiO 2 ). The wiring layer 4 is provided on the insulating film 3A. The wiring layer 4 is made of, for example, aluminum, an aluminum alloy (for example, an alloy of aluminum and copper or silicon), tungsten, titanium, titanium nitride, or the like. An opening 3Ah (contact hole) is formed in the insulating film 3A, and the wiring layer 4 is electrically connected to the semiconductor portion 2 (diffusion layer 2m) through the opening 3Ah.

絶縁膜３Ｂは、絶縁膜３Ａ及び配線層４上に設けられている。絶縁膜３Ｂは、例えばシリコン酸化物（例えばＳｉＯ２）からなる。絶縁膜３Ｂには、開口３Ｂｈが形成されており、配線層４は、この開口３Ｂｈを介して外部に露出している。配線層４における開口３Ｂｈから露出した部分は、例えば受光素子１から電気信号を取り出すためのワイヤが接続されるパッド部として用いられる。 The insulating film 3B is provided on the insulating film 3A and the wiring layer 4. The insulating film 3B is made of, for example, a silicon oxide (for example, SiO 2 ). An opening 3Bh is formed in the insulating film 3B, and the wiring layer 4 is exposed to the outside through the opening 3Bh. The portion of the wiring layer 4 exposed from the opening 3Bh is used as, for example, a pad portion to which a wire for extracting an electric signal from the light receiving element 1 is connected.

金属膜５は、絶縁膜３Ａ，３Ｂ及び配線層４上に設けられている。すなわち、金属膜５は、絶縁膜３Ａ，３Ｂ及び配線層４を介して、第１面１ｓ（遮光部１Ｂ）上に形成されている。なお、金属膜５は、絶縁膜３Ｂにのみ接触している。このため、金属膜５と配線層４とは、第１面１ｓに交差する方向からみて重複していても、互いの間に絶縁膜３Ｂが介在されており、互いに電気的に分離されている。一方、金属膜５には、開口３Ｂｈに対応する位置に開口５ｐが形成されている。したがって、遮光部１Ｂにおける開口５ｐに対応する位置には、金属膜５が設けられていないが、配線層４が配置されている。すなわち、受光素子１においては、遮光部１Ｂ上には、金属膜５と配線層４との少なくとも一方の金属が配置されており、遮光が得られている。 The metal film 5 is provided on the insulating films 3A and 3B and the wiring layer 4. That is, the metal film 5 is formed on the first surface 1s (light-shielding portion 1B) via the insulating films 3A and 3B and the wiring layer 4. The metal film 5 is in contact with the insulating film 3B only. Therefore, even if the metal film 5 and the wiring layer 4 overlap each other when viewed from the direction of intersection with the first surface 1s, the insulating film 3B is interposed between the metal film 5 and the wiring layer 4, and the metal film 5 and the wiring layer 4 are electrically separated from each other. .. On the other hand, the metal film 5 is formed with an opening 5p at a position corresponding to the opening 3Bh. Therefore, although the metal film 5 is not provided at the position corresponding to the opening 5p in the light-shielding portion 1B, the wiring layer 4 is arranged. That is, in the light receiving element 1, at least one metal of the metal film 5 and the wiring layer 4 is arranged on the light shielding portion 1B, and light shielding is obtained.

金属膜５は、例えば、アルミニウム、アルミニウム合金（例えば、アルミニウムと銅やシリコンとの合金）、タングステン、チタン、又は、窒化チタン等からなる。金属膜５は、例えば、配線層４と同一の工程・材料により構成されてもよい。金属膜５は、半導体部２の第１面１ｓと反対側に臨む第２面５ｓを有している。第２面５ｓは、外部に露出している。したがって、第２面５ｓは、光の入射を受ける受光面でもある。第２面５ｓには、複数の凹部６が形成されている。凹部６は、第２面５ｓの全体にわたって形成されている。引き続いて、この凹部６について説明する。 The metal film 5 is made of, for example, aluminum, an aluminum alloy (for example, an alloy of aluminum and copper or silicon), tungsten, titanium, titanium nitride, or the like. The metal film 5 may be composed of, for example, the same process and material as the wiring layer 4. The metal film 5 has a second surface 5s facing the first surface 1s of the semiconductor portion 2 and facing the opposite side. The second surface 5s is exposed to the outside. Therefore, the second surface 5s is also a light receiving surface that receives the incident light. A plurality of recesses 6 are formed on the second surface 5s. The recess 6 is formed over the entire second surface 5s. Subsequently, the recess 6 will be described.

図４は、図３に示された凹部を示す図である。図４の（ａ）は、図３の領域Ａの拡大平面図であり、図４の（ｂ），（ｃ）は単一の凹部を示すも断面図である。図４に示されるように、ここでは、凹部６は、第２面５ｓに交差（直交）する方向からみて、円形状である。凹部６の直径Ｄ（第２面５ｓにおける凹部６のサイズの最大値）は、例えば０．３μｍ～５μｍである。金属膜５の厚さＴ（第２面５ｓに交差する方向における金属膜５のサイズ）は、例えば、０．１μｍ～５μｍ程度である。凹部６の直径Ｄは、金属膜５の厚さＴに依存しない。例えばウェットエッチングにより凹部６を形成する場合、ウェットエッチングに要する時間を凹部６の底部６ｂの直下に金属膜５を残存させて遮光性を十分に維持できるように制御することで、任意に形成できる。 FIG. 4 is a diagram showing the recess shown in FIG. FIG. 4A is an enlarged plan view of the region A of FIG. 3, and FIGS. 4B and 4C are cross-sectional views showing a single recess. As shown in FIG. 4, here, the recess 6 has a circular shape when viewed from the direction intersecting (orthogonal) with the second surface 5s. The diameter D of the recess 6 (the maximum value of the size of the recess 6 on the second surface 5s) is, for example, 0.3 μm to 5 μm. The thickness T of the metal film 5 (the size of the metal film 5 in the direction intersecting the second surface 5s) is, for example, about 0.1 μm to 5 μm. The diameter D of the recess 6 does not depend on the thickness T of the metal film 5. For example, when the recess 6 is formed by wet etching, it can be arbitrarily formed by controlling the time required for wet etching so that the metal film 5 remains directly under the bottom 6b of the recess 6 so that the light-shielding property can be sufficiently maintained. ..

凹部６は、第２面５ｓに沿って（少なくとも１方向について）一定のピッチＰで配列されている。ピッチＰは、互いに隣り合う凹部６の中心同士の間隔である。ここでは、凹部６は、第２面５ｓに沿った２方向（互いに直交する方向）について同一のピッチＰで配列されている。ピッチＰは、例えば、０．６μｍ～２０μｍである。さらに、ピッチＰは、凹部６の直径Ｄよりも大きい。したがって、ピッチＰで互いに隣り合う凹部６の間には、凹部でない平坦な領域Ｒが生じている。換言すれば、第２面５ｓは、凹部６の周囲に設けられた平坦な領域Ｒを含む。さらに換言すれば、第２面５ｓにおいて、凹部６同士は連続しておらず、互いに離間している。 The recesses 6 are arranged at a constant pitch P along the second surface 5s (in at least one direction). The pitch P is the distance between the centers of the recesses 6 adjacent to each other. Here, the recesses 6 are arranged at the same pitch P in two directions (directions orthogonal to each other) along the second surface 5s. The pitch P is, for example, 0.6 μm to 20 μm. Further, the pitch P is larger than the diameter D of the recess 6. Therefore, a flat region R that is not a recess is formed between the recesses 6 adjacent to each other at the pitch P. In other words, the second surface 5s includes a flat region R provided around the recess 6. In other words, on the second surface 5s, the recesses 6 are not continuous and are separated from each other.

凹部６の内面６ｓは、曲面部７を有している。ここでは、曲面部７は、第２面５ｓから凹部６の底部６ｂに延びており、第２面５ｓから底部６ｂに向かうにつれて凹部６のサイズが縮小するように曲がっている。曲面部７の断面形状は、例えば円弧状である。図４の（ｂ）に示されるように、凹部６の内面６ｓは、第２面５ｓから延びる曲面部７と、底部６ｂに位置する平坦部８とを含む場合がある。或いは、図４の（ｃ）に示されるように、凹部６の内面６ｓの全体が曲面部７であってもよい。この場合、曲面部７は、凹部６の底部６ｂを構成するように延在している。この場合、凹部６の直径Ｄは、金属膜５の厚さＴ以下である。 The inner surface 6s of the recess 6 has a curved surface portion 7. Here, the curved surface portion 7 extends from the second surface 5s to the bottom portion 6b of the recess 6, and is bent so that the size of the recess 6 decreases toward the bottom portion 6b from the second surface 5s. The cross-sectional shape of the curved surface portion 7 is, for example, an arc shape. As shown in FIG. 4B, the inner surface 6s of the recess 6 may include a curved surface portion 7 extending from the second surface 5s and a flat portion 8 located at the bottom portion 6b. Alternatively, as shown in FIG. 4C, the entire inner surface 6s of the recess 6 may be a curved surface portion 7. In this case, the curved surface portion 7 extends so as to form the bottom portion 6b of the recess 6. In this case, the diameter D of the recess 6 is equal to or less than the thickness T of the metal film 5.

引き続いて、受光素子の製造方法について説明する。ここでは、説明の容易化のため、受光素子１の構成を簡素化した受光素子の製造方法について説明する。図５は、図３に示された受光素子を簡素化した受光素子を示す部分断面図である。図５に示されるように、受光素子１０は、絶縁膜３Ｂを有していない点と配線層４に代えてパッド部４Ａを備える点とにおいて受光素子１と相違している。受光素子１０の他の点は、受光素子１と同一である。 Subsequently, a method of manufacturing the light receiving element will be described. Here, for the sake of simplification of the description, a method of manufacturing a light receiving element in which the configuration of the light receiving element 1 is simplified will be described. FIG. 5 is a partial cross-sectional view showing a light receiving element that is a simplification of the light receiving element shown in FIG. As shown in FIG. 5, the light receiving element 10 is different from the light receiving element 1 in that it does not have the insulating film 3B and that the pad portion 4A is provided instead of the wiring layer 4. Other points of the light receiving element 10 are the same as those of the light receiving element 1.

この製造方法においては、まず、図６の（ａ）に示されるように、半導体部２、及び、開口３Ａｈが形成された絶縁膜３Ａを有する基体５０を用意する（工程Ｓ１０１）。続いて、図６の（ｂ）に示されるように、絶縁膜３Ａ上に、金属膜５及びパッド部４Ａのための金属膜５１を成膜する（工程Ｓ１０２、第１工程）。続いて、図７の（ａ）に示されるように、金属膜５１上にレジスト５２を塗布する（工程Ｓ１０３、第１工程）。続いて、図７の（ｂ）に示されるように、レジスト５２の露光及び現像によるパターニングを行い、マスク５３を形成する（工程Ｓ１０４、第１工程）。マスク５３には、受光部１Ａに対応する位置に開口５３ｈが形成されている。 In this manufacturing method, first, as shown in FIG. 6A, a substrate 50 having a semiconductor portion 2 and an insulating film 3A having an opening 3Ah formed is prepared (step S101). Subsequently, as shown in FIG. 6B, a metal film 51 for the metal film 5 and the pad portion 4A is formed on the insulating film 3A (step S102, first step). Subsequently, as shown in FIG. 7A, the resist 52 is applied onto the metal film 51 (step S103, first step). Subsequently, as shown in FIG. 7B, patterning by exposure and development of the resist 52 is performed to form the mask 53 (step S104, first step). The mask 53 is formed with an opening 53h at a position corresponding to the light receiving portion 1A.

続いて、図８の（ａ）に示されるように、マスク５３を用いて金属膜５１をエッチングする（工程Ｓ１０５、第１工程）。これにより、金属膜５１のうちの開口５３ｈに露出した部分を除去し、金属膜５４及びパッド部４Ａを形成する。金属膜５４は、後に金属膜５となる部分である。そして、図８の（ｂ）に示されるように、マスク５３を除去する（工程Ｓ１０６）。以上の工程Ｓ１０１～Ｓ１０６によって、半導体部２の第１面１ｓの一部に遮光のための金属膜５４を形成することにより、金属膜５４から露出した受光部１Ａと、金属膜５４に覆われた遮光部１Ｂと、を第１面１ｓに形成する。 Subsequently, as shown in FIG. 8A, the metal film 51 is etched using the mask 53 (step S105, first step). As a result, the portion of the metal film 51 exposed to the opening 53h is removed to form the metal film 54 and the pad portion 4A. The metal film 54 is a portion that will later become the metal film 5. Then, as shown in FIG. 8B, the mask 53 is removed (step S106). By forming the metal film 54 for shading on a part of the first surface 1s of the semiconductor portion 2 by the above steps S101 to S106, the light receiving portion 1A exposed from the metal film 54 and the metal film 54 are covered with the metal film 54. The light-shielding portion 1B and the light-shielding portion 1B are formed on the first surface 1s.

続いて、図９の（ａ）に示されるように、金属膜５４、絶縁膜３Ａ、及び、パッド部４Ａ上に、レジスト５５を塗布する（工程Ｓ２０１、第２工程）。続いて、図９の（ｂ）に示されるように、レジスト５５の露光及び現像によるパターニングを行い、マスク５６を形成する（工程Ｓ２０２、第２工程）。マスク５６には、凹部６に対応するように複数の開口５６ｈが形成されている。 Subsequently, as shown in FIG. 9A, the resist 55 is applied onto the metal film 54, the insulating film 3A, and the pad portion 4A (step S201, second step). Subsequently, as shown in FIG. 9B, patterning by exposure and development of the resist 55 is performed to form the mask 56 (step S202, second step). The mask 56 is formed with a plurality of openings 56h so as to correspond to the recess 6.

続いて、図１０の（ａ）に示されるように、マスク５６を用いて金属膜５４をエッチングすることにより、金属膜５４に複数の凹部６を形成し、金属膜５を形成する（工程Ｓ２０３、第２工程）。ここでのエッチングは、例えばウェットエッチング等の等方性のエッチングである。ここでは、マスク５６の開口５６ｈのサイズ及びピッチ、工程Ｓ２０３のエッチング時間等の制御により、凹部６の直径Ｄ及びピッチＰを制御できる。 Subsequently, as shown in FIG. 10A, the metal film 54 is etched with the mask 56 to form a plurality of recesses 6 in the metal film 54 to form the metal film 5 (step S203). , Second step). The etching here is isotropic etching such as wet etching. Here, the diameter D and the pitch P of the recess 6 can be controlled by controlling the size and pitch of the opening 56h of the mask 56, the etching time of the step S203, and the like.

そして、図１０の（ｂ）に示されるように、マスク５６を除去する（工程Ｓ２０４）。以上の工程Ｓ２０１～Ｓ２０４によって、金属膜５４における第１面１ｓと反対側に臨む第２面の等方性のエッチングにより、第２面（第２面５ｓ）に複数の凹部６を形成する。これにより、受光素子１０が得られる。 Then, as shown in FIG. 10B, the mask 56 is removed (step S204). By the above steps S201 to S204, a plurality of recesses 6 are formed on the second surface (second surface 5s) by isotropic etching of the second surface of the metal film 54 facing the side opposite to the first surface 1s. As a result, the light receiving element 10 is obtained.

以上説明したように、受光素子１，１０においては、半導体部２の第１面１ｓの遮光部１Ｂ上に、遮光のための金属膜５が形成されている。金属膜５は、第１面１ｓと反対側に臨む第２面５ｓを有する。第２面５ｓには、複数の凹部６が形成されている。そして、凹部６の内面６ｓは、金属膜５の第２面５ｓから凹部６の底部６ｂに向かうにつれて凹部６が縮小するように曲がる曲面部７を含む。このため、金属膜５の第２面５ｓに入射した光の一部が、凹部６の内面６ｓの曲面部７によって種々の方向に反射されて拡散される。この結果、遮光部１Ｂにおける反射率が低減される。 As described above, in the light receiving elements 1 and 10, a metal film 5 for light shielding is formed on the light shielding portion 1B of the first surface 1s of the semiconductor portion 2. The metal film 5 has a second surface 5s facing the opposite side of the first surface 1s. A plurality of recesses 6 are formed on the second surface 5s. The inner surface 6s of the recess 6 includes a curved surface portion 7 that bends so that the recess 6 shrinks from the second surface 5s of the metal film 5 toward the bottom 6b of the recess 6. Therefore, a part of the light incident on the second surface 5s of the metal film 5 is reflected and diffused in various directions by the curved surface portion 7 of the inner surface 6s of the recess 6. As a result, the reflectance in the light-shielding portion 1B is reduced.

また、受光素子１，１０においては、凹部６の直径Ｄは、金属膜５の厚さＴに依存しない。例えばウェットエッチングにより凹部６を形成する場合、ウェットエッチングに要する時間を凹部６の底部６ｂの直下に金属膜５を残存させて遮光性を十分に維持できるように制御することで、任意に形成できる。 Further, in the light receiving elements 1 and 10, the diameter D of the recess 6 does not depend on the thickness T of the metal film 5. For example, when the recess 6 is formed by wet etching, it can be arbitrarily formed by controlling the time required for wet etching so that the metal film 5 remains directly under the bottom 6b of the recess 6 so that the light-shielding property can be sufficiently maintained. ..

また、受光素子１，１０においては、曲面部７は、底部６ｂを構成するように延在していてもよい。この場合、凹部６の内面６ｓの全体が曲面部７となるため、入射光を確実に拡散させることができる。 Further, in the light receiving elements 1 and 10, the curved surface portion 7 may extend so as to form the bottom portion 6b. In this case, since the entire inner surface 6s of the recess 6 becomes the curved surface portion 7, the incident light can be reliably diffused.

また、受光素子１，１０においては、第２面５ｓは、凹部６の周囲に設けられた平坦な領域Ｒを含んでいる。このため、第２面５ｓにおける平坦な領域Ｒで反射した光と、凹部６の内面６ｓで反射した光との干渉によって、反射率を確実に低減可能である。 Further, in the light receiving elements 1 and 10, the second surface 5s includes a flat region R provided around the recess 6. Therefore, the reflectance can be reliably reduced by the interference between the light reflected by the flat region R on the second surface 5s and the light reflected by the inner surface 6s of the recess 6.

さらに、受光素子１，１０においては、凹部６は、第２面５ｓに沿って一定のピッチＰで配列されている。このため、凹部６の形成を容易化できる。 Further, in the light receiving elements 1 and 10, the recesses 6 are arranged at a constant pitch P along the second surface 5s. Therefore, the formation of the recess 6 can be facilitated.

ここで、上述した製造方法によれば、受光部１Ａと遮光部１Ｂとを含む第１面１ｓを有する半導体部２と、遮光部１Ｂ上に設けられ、複数の凹部６が形成された金属膜５と、を備える受光素子１，１０が製造される。特に、金属膜５４の第２面の等方性エッチングによって、凹部６の内面６ｓを、金属膜５の第２面５ｓから凹部６の底部６ｂに向かうにつれて凹部６が縮小するように曲がる曲面部７を含むように形成できる。したがって、この製造方法によれば、遮光部１Ｂにおける反射率が低減された受光素子１，１０を製造できる。 Here, according to the manufacturing method described above, the semiconductor portion 2 having the first surface 1s including the light receiving portion 1A and the light shielding portion 1B, and the metal film provided on the light shielding portion 1B and having a plurality of recesses 6 formed therein. Light receiving elements 1 and 10 comprising 5 and 5 are manufactured. In particular, a curved surface portion in which the inner surface 6s of the recess 6 is bent so that the inner surface 6s of the recess 6 is reduced from the second surface 5s of the metal film 5 toward the bottom 6b of the recess 6 by isotropic etching of the second surface of the metal film 54. It can be formed to include 7. Therefore, according to this manufacturing method, the light receiving elements 1 and 10 having a reduced reflectance in the light shielding portion 1B can be manufactured.

また、上述した製造方法においては、等方性のエッチングは、ウェットエッチングである。このため、ドライエッチングと比較して、エッチングにより形成される凹部６の内面６ｓが粗面化される。このため、遮光部１Ｂにおける反射率がより低減された受光素子１，１０を製造できる。 Further, in the above-mentioned manufacturing method, the isotropic etching is wet etching. Therefore, as compared with dry etching, the inner surface 6s of the recess 6 formed by etching is roughened. Therefore, the light receiving elements 1 and 10 having a reduced reflectance in the light shielding portion 1B can be manufactured.

引き続いて、上述した受光素子の実施例及び比較例について説明する。図１１は、実施例及び比較例に係る受光素子の金属膜の一部を示す写真である。図１１の（ａ）は、実施例に係る受光素子の金属膜の第２面の写真である。図１１の（ｂ）は、比較例に係る受光素子の金属膜の第２面の写真である。図１１に示される実施例では、金属膜５の材料をアルミニウムとし、マスク５６の開口５６ｈのサイズを０．８μｍとし、ウェットエッチングにより１０秒間のエッチングを行った。エッチング剤は、リン酸を含む混酸とした。一方、比較例では、金属膜の材料及びマスクの開口のサイズを実施例と同一にしつつ、３２秒間のドライエッチングを行った。ここでは、異方性のドライエッチングは、ＥＣＲ方式とした（ただし、異方性のドライエッチングはＩＣＰ方式としてもよい）。 Subsequently, examples and comparative examples of the above-mentioned light receiving element will be described. FIG. 11 is a photograph showing a part of the metal film of the light receiving element according to the examples and the comparative examples. FIG. 11A is a photograph of the second surface of the metal film of the light receiving element according to the embodiment. FIG. 11B is a photograph of the second surface of the metal film of the light receiving element according to the comparative example. In the example shown in FIG. 11, the material of the metal film 5 was aluminum, the size of the opening 56h of the mask 56 was 0.8 μm, and etching was performed for 10 seconds by wet etching. The etching agent was a mixed acid containing phosphoric acid. On the other hand, in the comparative example, dry etching was performed for 32 seconds while keeping the material of the metal film and the size of the opening of the mask the same as those in the example. Here, the anisotropic dry etching is performed by the ECR method (however, the anisotropic dry etching may be performed by the ICP method).

図１１の（ａ）に示されるように、実施例においては、第２面から底部に向かうにつれて縮小するように曲がる曲面部を含む複数の凹部６が形成された。これに対して、図１１の（ｂ）に示されるように、比較例においては、第２面から底部に向かう方向に平坦に延びる内面の凹部６Ａが形成された。 As shown in FIG. 11A, in the embodiment, a plurality of recesses 6 including a curved surface portion that bends so as to shrink from the second surface toward the bottom portion are formed. On the other hand, as shown in FIG. 11B, in the comparative example, a recess 6A on the inner surface extending flatly from the second surface toward the bottom was formed.

図１２は、実施例及び比較例に係る受光素子の反射率を示すグラフである。図１２においては、実施例に係る受光素子（金属膜）の反射率Ｌ１を実線で示し、比較例に係る受光素子（金属膜）の反射率Ｌ２を破線で示している。図１２に示されるように、実施例に係る反射率Ｌ１は、波長３８０ｎｍ～波長１０４０ｎｍの測定範囲のほぼ全域において、比較例に係る反射率Ｌ２を下回った。特に、実施例に係る反射率Ｌ１は、波長５８０ｎｍ～波長１０４０ｎｍの範囲において、２０％を下回っており、反射率が十分に低減されることが確認された。 FIG. 12 is a graph showing the reflectance of the light receiving element according to the examples and the comparative examples. In FIG. 12, the reflectance L1 of the light receiving element (metal film) according to the embodiment is shown by a solid line, and the reflectance L2 of the light receiving element (metal film) according to the comparative example is shown by a broken line. As shown in FIG. 12, the reflectance L1 according to the example was lower than the reflectance L2 according to the comparative example in almost the entire measurement range of the wavelength 380 nm to the wavelength 1040 nm. In particular, the reflectance L1 according to the examples was less than 20% in the wavelength range of 580 nm to 1040 nm, and it was confirmed that the reflectance was sufficiently reduced.

以上の実施形態は、本発明に係る受光素子、及び、受光素子の製造方法の一実施形態を説明したものである。したがって、本発明に係る受光素子、及び、受光素子の製造方法は、上記の実施形態に限定されず、任意に変更され得る。引き続いて、変形例について説明する。 The above-described embodiment describes the light-receiving element according to the present invention and one embodiment of the method for manufacturing the light-receiving element. Therefore, the light receiving element according to the present invention and the method for manufacturing the light receiving element are not limited to the above-described embodiment, and can be arbitrarily changed. Subsequently, a modified example will be described.

図１３は、変形例に係る受光素子の例えば、上述した受光素子１０は、図１３に示されるように変更してもよい。図１３に示される受光素子１０Ａは、受光素子１０と比較して、拡散層２ｍが変更されている。受光素子１０Ａにおいて、拡散層２ｍは、受光部１Ａの下部の領域から、金属膜５及び遮光部１Ｂの下部の領域を越えて延在している。そして、拡散層２ｍは、金属膜５の開口５ｐに対応する位置において、パッド部４Ａと接触して電気的に接続されている。このように、拡散層２ｍを配線層として使用してもよい。 In FIG. 13, for example, the light receiving element 10 described above of the light receiving element according to the modified example may be changed as shown in FIG. In the light receiving element 10A shown in FIG. 13, the diffusion layer 2 m is changed as compared with the light receiving element 10. In the light receiving element 10A, the diffusion layer 2m extends from the lower region of the light receiving portion 1A beyond the lower region of the metal film 5 and the light shielding portion 1B. The diffusion layer 2m is in contact with the pad portion 4A and electrically connected at a position corresponding to the opening 5p of the metal film 5. In this way, the diffusion layer 2 m may be used as the wiring layer.

図１４は、変形例に係る金属膜を示す図である。図１４に示される金属膜５においては、凹部６のピッチＰが凹部６の直径Ｄと略一致している。このため、ピッチＰで互いに隣接する凹部６の間には、平坦な領域Ｒが実質的に形成されていない。ただし、ピッチＰと異なるピッチで隣り合う凹部６（ピッチＰでの２つの配列方向に交差する方向に隣り合う凹部６）の間には、平坦な領域Ｒが形成される。この場合には、図４の（ａ）に示される場合と比較して、第２面５ｓにおける凹部６の占める面積と領域Ｒが占める面積との割合が異なる。このように、所望する反射の態様に応じて、凹部６と領域Ｒとの面積比を適宜制御することができる。 FIG. 14 is a diagram showing a metal film according to a modified example. In the metal film 5 shown in FIG. 14, the pitch P of the recess 6 substantially coincides with the diameter D of the recess 6. Therefore, a flat region R is not substantially formed between the recesses 6 adjacent to each other at the pitch P. However, a flat region R is formed between the recesses 6 adjacent to each other at a pitch different from the pitch P (the recesses 6 adjacent to each other in the direction intersecting the two arrangement directions at the pitch P). In this case, the ratio of the area occupied by the recess 6 and the area occupied by the region R on the second surface 5s is different from the case shown in FIG. 4A. In this way, the area ratio between the recess 6 and the region R can be appropriately controlled according to the desired mode of reflection.

図１５及び図１６は、変形例に係る金属膜を示す平面図である。図１５の（ａ）に示されるように、金属膜５においては、凹部６のピッチ及びサイズをランダムとしてもよい。なお、凹部６のピッチ及びサイズのいずれか一方をランダムとしてもよい。また、図１５の（ｂ）及び図１６の（ｂ）に示されるように、凹部６の平面形状を、六角形状や四角形状といったように、円形状以外の形状としてもよい。さらには、図１５の（ｂ）及び図１６の（ａ）に示されるように、凹部６の配列のピッチを、互いに４５°の角度で交差する２方向において等しくし、三角格子状に凹部６を配列してもよい。 15 and 16 are plan views showing a metal film according to a modified example. As shown in FIG. 15A, in the metal film 5, the pitch and size of the recesses 6 may be random. Either the pitch or the size of the recess 6 may be random. Further, as shown in (b) of FIG. 15 and (b) of FIG. 16, the planar shape of the recess 6 may be a shape other than a circular shape such as a hexagonal shape or a square shape. Further, as shown in (b) of FIG. 15 and (a) of FIG. 16, the pitch of the arrangement of the recesses 6 is made equal in two directions intersecting each other at an angle of 45 °, and the recesses 6 are formed in a triangular lattice pattern. May be arranged.

また、上記実施形態においては、凹部６の形成のための等方性のエッチングとしてウェットエッチングを例示したが、例えば、ケミカドライエッチングといった等方性のドライエッチングを利用することもできる。 Further, in the above embodiment, wet etching is exemplified as isotropic etching for forming the recess 6, but isotropic dry etching such as chemica dry etching can also be used.

さらに、上記実施形態においては、受光素子１がロータリーエンコーダに用いられる例について説明したが、本実施形態に係る受光素子１，１０，１０Ａは、これに限定されず、任意の状況での利用が可能である。 Further, in the above embodiment, an example in which the light receiving element 1 is used for the rotary encoder has been described, but the light receiving elements 1, 10 and 10A according to the present embodiment are not limited to this, and can be used in any situation. It is possible.

１，１０，１０Ａ…受光素子、１ｓ…第１面、１Ａ…受光部、１Ｂ…遮光部、２…半導体部、５…金属膜、５ｓ…第２面、６…凹部、６ｓ…内面、６ｂ…底部、７…曲面部、Ｒ…領域。 1,10,10A ... light receiving element, 1s ... first surface, 1A ... light receiving part, 1B ... shading part, 2 ... semiconductor part, 5 ... metal film, 5s ... second surface, 6 ... recess, 6s ... inner surface, 6b ... bottom, 7 ... curved surface, R ... area.

Claims (6)

受光部と遮光部とを含む第１面を有する半導体部と、
前記遮光部上に設けられた遮光のための金属膜と、
を備え、
前記金属膜は、前記第１面と反対側に臨み光の入射を受ける第２面を有し、
前記第２面には、複数の凹部が形成されており、
前記凹部の内面は、前記第２面から前記凹部の底部に向かうにつれて前記第２面に沿った方向における前記凹部のサイズが縮小するように曲がる曲面部を含み、
前記第２面は、前記凹部の周囲に設けられた平坦な領域を含む、
受光素子。 A semiconductor portion having a first surface including a light receiving portion and a light shielding portion,
A metal film for shading provided on the light-shielding portion and
With
The metal film has a second surface facing the first surface and receiving light incident on the opposite side.
A plurality of recesses are formed on the second surface.
The inner surface of the recess includes a curved surface that bends so that the size of the recess in the direction along the second surface decreases from the second surface toward the bottom of the recess.
The second surface includes a flat area provided around the recess.
Light receiving element. 前記曲面部は、前記底部を構成するように延在している、
請求項１に記載の受光素子。 The curved surface portion extends so as to form the bottom portion.
The light receiving element according to claim 1. 前記第２面における前記凹部のサイズは、前記第２面に交差する方向における前記金属膜のサイズ以下である、
請求項２に記載の受光素子。 The size of the recess on the second surface is less than or equal to the size of the metal film in the direction intersecting the second surface.
The light receiving element according to claim 2. 前記凹部は、前記第２面に沿って一定のピッチで配列されている、
請求項１～３のいずれか一項に記載の受光素子。 The recesses are arranged at a constant pitch along the second surface.
The light receiving element according to any one of claims 1 to 3 . 半導体部の第１面の一部上に遮光のための金属膜を形成することにより、前記金属膜から露出した受光部と前記金属膜に覆われた遮光部とを前記第１面に形成する第１工程と、
前記金属膜における前記第１面と反対側に臨む第２面の等方性のエッチングにより、前記第２面に複数の凹部を形成する第２工程と、
を備え、
前記第２面は、前記凹部の周囲に設けられた平坦な領域を含む、
受光素子の製造方法。 By forming a metal film for shading on a part of the first surface of the semiconductor portion, a light receiving portion exposed from the metal film and a shading portion covered with the metal film are formed on the first surface. First step and
A second step of forming a plurality of recesses on the second surface by isotropic etching of the second surface of the metal film facing the opposite side of the first surface.
With
The second surface includes a flat area provided around the recess.
Manufacturing method of light receiving element. 前記等方性のエッチングは、ウェットエッチングである、
請求項５に記載の受光素子の製造方法。 The isotropic etching is wet etching.
The method for manufacturing a light receiving element according to claim 5 .
JP2018080000A 2018-04-18 2018-04-18 Light receiving element and manufacturing method of light receiving element Active JP7103832B2 (en)

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JP2018080000A JP7103832B2 (en) 2018-04-18 2018-04-18 Light receiving element and manufacturing method of light receiving element
EP19788839.9A EP3783674A4 (en) 2019-04-09 Light reception element and method for manufacturing light-reception element
US17/042,509 US11380724B2 (en) 2018-04-18 2019-04-09 Light reception element and method for manufacturing light-reception element
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000227610A (en) 1999-02-05 2000-08-15 Seiko Epson Corp Method for formation of scattering face, production of liquid crystal display device and electronic appliance
WO2013061990A1 (en) 2011-10-24 2013-05-02 旭硝子株式会社 Optical filter, method for producing same, and image capturing device
JP2014241351A (en) 2013-06-12 2014-12-25 パナソニック株式会社 Optical semiconductor device with concave-convex part and method for manufacturing the same
JP2015079232A (en) 2013-07-09 2015-04-23 旭硝子株式会社 Optical element, projection device, and method for manufacturing optical element

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS54154382A (en) * 1978-05-25 1979-12-05 Canon Inc Photo sensor device
JPH0484462A (en) 1990-07-27 1992-03-17 Nec Corp Photoconducting type infrared detector
JP2774006B2 (en) * 1991-12-25 1998-07-09 三菱電機株式会社 Semiconductor light receiving device and method of manufacturing the same
JPH10112552A (en) * 1996-10-03 1998-04-28 Sony Corp Semiconductor device
JP3503410B2 (en) * 1997-04-10 2004-03-08 株式会社デンソー Optical sensor adjustment method and optical sensor adjustment device
KR100813027B1 (en) 2001-08-18 2008-03-14 삼성전자주식회사 Methods for forming photosensitive insulating film pattern and reflection electrode each having irregular upper surface and method for manufacturing LCD having reflection electrode using the same
JP3730232B2 (en) 2003-04-24 2005-12-21 ファナック株式会社 Optical encoder
CN104871043B (en) * 2012-12-28 2017-09-26 旭硝子株式会社 The manufacture method of optical element, projection arrangement and optical element
US9608023B1 (en) * 2016-05-02 2017-03-28 Omnivision Technologies, Inc. Edge reflection reduction

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000227610A (en) 1999-02-05 2000-08-15 Seiko Epson Corp Method for formation of scattering face, production of liquid crystal display device and electronic appliance
WO2013061990A1 (en) 2011-10-24 2013-05-02 旭硝子株式会社 Optical filter, method for producing same, and image capturing device
JP2014241351A (en) 2013-06-12 2014-12-25 パナソニック株式会社 Optical semiconductor device with concave-convex part and method for manufacturing the same
JP2015079232A (en) 2013-07-09 2015-04-23 旭硝子株式会社 Optical element, projection device, and method for manufacturing optical element

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